(1) Field of the Invention
This invention is in the field of cable control systems and more specifically relates to two cable mechanical control systems having the capability to operate when one of the two cables is severed.
(2) Description of the Prior Art
Cable actuated control systems are well known in the art, often being used in light aircraft to effectuate movement in the aerodynamic surfaces. The use of a two cable configuration, in which the output actuator is driven by a quadrant connection of the cable, is a fairly standard technique of interfacing control cables with an output actuator so as to retain full control in either direction of movement. Though the prior art does contain teachings of apparatus for removing slack from such control cables, for example U.S. Pat. No. 2,810,300 and No. Re 23,933, the applicant is not aware of an apparatus for retaining control of the output actuator in the presence of a complete cable separation.
The designers of military aircraft are especially concerned with the survivability aspects of an aircraft's mechanisms, namely their ability to retain the aircraft airworthy after it sustains battle damage, such as having a control cable severed. The prior art does address itself to the problem of preventing the hardover position of free vibration usually occurring after a cable break in a two cable control system. A representative device is shown in U.S. Pat. No. 3,599,507. Since the control rod in this invention is centered to a neutral position by the opposing action of two springs, the apparatus mitigates only the secondary effects of a cable separation, acquiescing to the loss of control between pilot's end and the output actuator end of the cables.